.ajax-loader {
    display:    none;
    position:   fixed;
    z-index:    10000;
    top:        0;
    left:       0;
    height:     100%;
    width:      100%;
    background: /* rgba( 255, 255, 255, .8 )  */
                url('../images/loader.gif') 
                50% 50% 
                no-repeat;
}

body.loading .ajax-loader {
    overflow: hidden;   
}

body.loading .ajax-loader {
    display: block;
}